Yarn incorporating fluoropolymer staple fiber

ABSTRACT

Yarns made from staple fibers comprising a plurality of fluoropolymer staple fibers with an average caliper diameter of at least 15 micron and a plurality of non-fluoropolymer staple fibers, wherein the ratio of the average caliper diameter of the fluoropolymer staple fibers to the non-fluoropolymer staple fibers in the yarn is 1.2 or greater. Also taught are yarns made from staple fibers with a plurality of fluoropolymer staple fibers having a rectangular cross-section and with an average caliper diameter up to 500 micron, and a plurality of non-fluoropolymer staple fibers with an average caliper diameter up to 40 micron.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to the field of yarns incorporating fluoropolymer staple fibers and articles made therefrom.

BACKGROUND OF THE DISCLOSURE

Fluoropolymers have been used in yarns and ropes as friction modifiers in various forms. For example, U.S. Pat. No. 6,132,866, to Nelson et al., is directed to a staple yarn comprising a blend of 35 to 90 weight percent fluoropolymer fiber and 65 to 10 weight percent of one or more types of blend fibers.

Japanese Patent Application HEI 1 [1989]-139833 discloses a fiber material having good flexibility made by mixing less than 30% polytetrafluoroethylene fibers or strands with natural and/or synthetic fibers. Fabrics and clothing made with the fiber material of this publication have both good draping and improved anti-pilling properties.

Despite the teaching of the prior art, there remains a need for improved yarns incorporating fluoropolymer staple fibers in combination with other staple fibers to achieve performance advantages heretofore unachievable by the prior art.

SUMMARY OF THE DISCLOSURE

Covered embodiments are defined by the claims, not this summary. This summary is a high-level overview of various aspects and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification, any or all drawings, and each claim.

Disclosed herein in a first embodiment is a yarn comprising a i) plurality of fluoropolymer staple fibers with an average caliper diameter, sometimes referred to herein as a Feret diameter, of at least 15 micrometers (μm), and ii) a plurality of non-fluoropolymer staple fibers, said fluoropolymer staple fibers and non-fluoropolymer staple fibers, wherein the ratio of the average caliper diameter of the fluoropolymer staple fibers to the non-fluoropolymer staple fibers in the yarn is 1.2 or greater.

In an alternative embodiment, the non-fluoropolymer staple fibers may comprise a plurality of average caliper diameters. In any of the previous embodiments, the non-fluoropolymer staple fibers comprise one or more synthetic polymers. In any of the previous embodiments, the non-fluoropolymer staple fibers comprise one or more natural fibers. In any of the previous embodiments, the non-fluoropolymer staple fibers comprise both synthetic and natural fibers. In any of the previous embodiments, the fluoropolymer staple fiber has a substantially rectangular cross-section. In any of the previous embodiments, when the yarn is viewed in cross-section, the plurality of fluoropolymer staple fibers are oriented primarily in the outer region of the cross-section; and wherein the yarn has a yarn perimeter and at least a portion of the fluoropolymer staple fibers extend outwardly beyond the yarn perimeter. In any of the previous embodiments, the fluoropolymer is expanded polytetrafluoroethylene (ePTFE). In an alternative embodiment, the fluoropolymer is ePTFE having density of 1.9 grams per cubic centimeter (g/cm³) or less. In any of the previous embodiments, the yarn contains at least one of an antistatic component, a cohesion component, a wax, antimicrobial material, fragrance, antimildew agent, insect repellants, cooling agents, heating agents, analgesics, oleophobics, oleophilics, FR materials, an organic pigment, an inorganic pigment, a signature identification marker or a combination thereof. In any of the previous embodiments, the yarn further comprises at least one filler. In any of the previous embodiments, the yarn further contains an antimicrobial. In any of the previous embodiments, the ePTFE has a substantially rectangular cross section. In any of the previous embodiments, the yarn further comprises at least one continuous filament. In any of the previous embodiments, the continuous filament comprises an elastic filament. When measuring the staple fiber diameters in yarns that incorporate one or more continuous filament, it should be understood that the continuous filament component is not included in the staple fiber measurement(s). In any of the previous embodiments, the weight percent of fluoropolymer staple fiber in the yarn is 35% or less, based on the total weight of the yarn. In any of the previous embodiments, the yarn of the invention may be combined with other yarns into finished articles.

In an alternative embodiment, the present invention is directed to yarns made from staple fibers comprising a plurality of fluoropolymer staple fibers having a substantially rectangular cross-section and a plurality of non-fluoropolymer staple fibers, wherein the average caliper diameter of the fluoropolymer staple fibers is between 15 and 500 μm and the average caliper diameter of the non-fluoropolymer staple fibers is between 0.1 and 40 μm. In any of the previous embodiments, the non-fluoropolymer staple fibers comprise one or more average caliper diameters. In any of the previous embodiments, the non-fluoropolymer staple fibers comprise one or more of synthetic polymers, natural fibers and combinations thereof. In any of the previous embodiments, when the yarn is viewed in cross-section, the plurality of fluoropolymer staple fibers are oriented primarily in the outer region of the cross-section; and wherein the yarn has a yarn perimeter and at least a portion of the fluoropolymer staple fibers extend outwardly beyond the yarn perimeter. In any of the previous embodiments, the fluoropolymer comprises ePTFE. In any of the previous embodiments, the fluoropolymer is ePTFE having density of 1.9 g/cm³ or less. In any of the previous embodiments, the yarn contains at least one of an antistatic component, a cohesion component, a wax, antimicrobial material, fragrance, antimildew agent, insect repellants, cooling agents, heating agents, analgesics, oleophobics, oleophilics, FR materials, signature identification marker or a combination thereof. In any of the previous embodiments, the yarn further comprises at least one filler. In any of the previous embodiments, the yarn further comprises at least one continuous filament. In any of the previous embodiments, the continuous filament comprises an elastic filament. As noted above, when measuring the staple fiber diameters in yarns that incorporate one or more continuous filament, it should be understood that the continuous filament component is not included in the staple fiber measurement(s). In any of the previous embodiments, the weight percent of fluoropolymer in the yarn is 35% or less, based on the total weight of the yarn. In any of the previous embodiments, the yarn of the invention may be combined with other yarns.

The yarns of the present invention may be incorporated into a variety of articles including, but not limited to textiles, whether woven, knitted, nonwoven, fleece, and the like. Articles incorporating the unique yarns may be in the form of garments, footwear, carpets, architectural structures, flags, umbrellas and other articles which incorporate yarns therein.

Disclosed in other embodiments are yarns comprising i) a plurality of expanded PTFE (ePTFE) staple fibers with an average length of 1.25 inches and an average maximum caliper diameter, sometimes referred to herein as a Feret diameter, of at least 15 micrometers (μm), and ii) a plurality of polyester staple fibers, said ePTFE staple fibers and polyester staple fibers formed into a yarn where the weight percent of the ePTFE fiber is 10%, based on the total weight of the yarn, and wherein the ratio of the average maximum caliper diameter of the ePTFE staple fibers to the polyester staple fibers in the yarn is 1.2 or greater.

These and other unique features of the disclosure are described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot of Yarn Hairiness versus PTFE density.

FIG. 2 is a plot of hand (in grams) versus the percent ePTFE staple fiber blended into a knitted fabric comprising the m-aramid/ePTFE staple fiber yarn of the examples.

FIG. 3 is a plot of hand (in grams) versus the percent ePTFE staple fiber blended into a knitted fabric comprising the wool/ePTFE staple fiber yarn of the examples.

DEFINITIONS

“Titer” is the weight per unit length of a fiber or filament. The units of titer are dtex, tex and denier. Tex is the mass of the fiber or filament in grams per 1000 meters of length; dtex is the mass of the fiber or filament in grams per 10,000 meters of length or equivalently 10 dtex=1 tex. Denier is the mass of the fiber or filament in grams per 9000 meters of length or equivalently 0.9*dtex=denier.

“Denier per fiber” refers to the average denier of staple fibers formed from a tow, for example, a fluoropolymer tow. The staple fibers will typically have a variety of denier, so the denier per fiber refers to the average denier of a representative sample of the staple fibers.

“Towing” is the operation which fibrillates mono filament into an array of fiber elements joined at each distal end creating a diamond like or parallelogram configuration through the surface of the original monofilament. A “tow” filament is one that has undergone a towing operation. A tow filament can later be cut into staple fiber.

“Fiber” means a natural or synthetic material that has a length that is much greater than its width.

“Filament” means a continuous fiber that has a length that is generally measured in meters and can be tens, hundreds or even thousands of meters long. To render the filament into a staple fiber, the filament may be cut or sheared, for example, using a guillotine or rotatory blade mechanism such as available from the DM & E Company located in Shelby, N.C. The desired cut length is determined by which staple process (e.g., long or short staple process) and the type of spinning process to be used. In some embodiments, when blending different types of staple fiber together to form a spun yarn, the length of the staple fiber are similar, for example the average staple lengths can be within 10% or less of each other. In other embodiments, when blending different types of staple fiber together to form a spun yarn, the length of the staple fiber can be greater than 10% of each other.

“Staple fiber” means a fiber that has a finite length that is generally measured in centimeters (cm). A staple fiber is generally characterized as an element having an aspect ratio (length to width) of greater than about 50 to one and an overall length of less than 250 mm. For purposes of this disclosure, the term staple fiber may sometimes be used to refer to either natural or synthetic fibers.

“Synthetic fiber” means a manmade fiber.

The term “substantially rectangular configuration” as used herein is meant to denote that the staple fibers have a rectangular or nearly rectangular cross section, with or without a rounded or pointed edge (or side) and a cross sectional aspect ratio, for example, width to height, greater than 1. Prior to incorporation into a yarn, the fluoropolymer staple fibers described herein can have a cross section that is substantially rectangular. After incorporation into the yarn, the cross section of the fluoropolymer staple fibers can be an irregular rectangular cross section, i.e., still having an aspect ratio of greater than 1.

“Average caliper diameter” means the average of the largest cross-sectional diameter measurement of a staple fiber. A technique for determining the average caliper diameter is discussed herein.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure is directed to yarns incorporating fluoropolymer staple fibers and articles therefrom. The yarn comprises i) a plurality of fluoropolymer staple fibers with an average caliper diameter of at least 15 micrometers and ii) a plurality of non-fluoropolymer staple fibers, and wherein the ratio of the average caliper diameter of the fluoropolymer staple fibers to the non-fluoropolymer staple fibers in the yarn is 1.2 or greater. In other embodiments, the yarn consists of or consists essentially of a plurality of fluoropolymer staple fibers, and a plurality of non-fluoropolymer staple fibers, and wherein the ratio of the average caliper diameter of the fluoropolymer staple fibers to the non-fluoropolymer staple fibers in the yarn is 1.2 or greater. The method for determining the average caliper diameter is described herein and the ratio of the average caliper diameter of the fluoropolymer staple fibers to the non-fluoropolymer staple fibers can be in the range of from 1.2 to less than or equal to 20. In another embodiment, the yarn comprises (i) a plurality of fluoropolymer staple fibers having a rectangular cross-section; and (ii) a plurality of non-fluoropolymer staple fibers, wherein the average caliper diameter of the fluoropolymer staple fibers is between 15 and 500 micrometers and the average caliper diameter of the non-fluoropolymer staple fiber is between 0.1 and 40 micrometers. In another embodiment, the yarn consists of or consists essentially of (i) a plurality of fluoropolymer staple fibers having a rectangular cross-section; and (ii) a plurality of non-fluoropolymer staple fibers, wherein the average caliper diameter of the fluoropolymer staple fibers is between 15 and 500 micrometers and the average caliper diameter of the non-fluoropolymer staple fiber is between 0.1 and 40 micrometers.

The fluoropolymer staple fibers can be produced from fluoropolymer filaments or a fluoropolymer tow. Suitable fluoropolymers may comprise any suitable fluoropolymers capable of being formed into filaments or tow, for example, homopolymers and copolymers comprising tetrafluoroethylene. Suitable comonomers can include, for example, ethylene, propylene, vinylidene fluoride, vinylidene chloride, acrylates, methacrylates, fluoroacrylates, fluoromethacrylates or a combination thereof. Any known additive can be added to the fluoropolymers prior to or after staple fiber formation. In some embodiments, the additive can be added prior to fiber formation so that the polymer matrix is filled with the additive. Suitable fillers can be, for example organic fillers, inorganic fillers, thermally conductive, electrically conductive, thermally insulates, electrically insulates, silver, carbon black, color pigments, color lakes, color dyes, size/dimensionally enhancing materials, signature identification markers, UV absorbers, light reflecting materials or a combination thereof. The fluoropolymers can then be formed into filaments or tow having the desired caliper diameter by any known method. The filaments and/or the tow can then be cut or otherwise shortened into staple fibers having the desired length.

In some embodiments, the fluoropolymer staple fiber can be polytetrafluoroethylene (PTFE) staple fiber or expanded polytetrafluoroethylene (ePTFE) staple fiber. In a further embodiment, the fluoropolymer staple fiber is ePTFE staple fiber. Suitable ePTFE can have a density of 1.9 grams per cubic centimeter (g/cm³) or less, for example, between 0.2 and 1.9 g/cm³. The tenacity of full density, non-expanded PTFE staple is typically less than 1.8 grams/denier (g/d). In contrast, the tenacity of ePTFE is greater, and typically greater than 1.6 g/d. In other embodiments, the ePTFE can have a tenacity of greater than 1.7 g/d, or greater than 1.8 g/d, or greater than 1.9 g/d, or greater than 2.0 g/d, or even greater than 2.3 g/d, which can provide for a stronger fiber in the yarn which can result in improved fray resistance, tensile strength and abrasion resistance.

In some embodiments, polytetrafluoroethylene (PTFE) and expanded polytetrafluoroethylene (ePTFE) can be produced in a ribbon like form as disclosed in U.S. Pat. No. 3,953,566 to Gore. Full density (that is, non-expanded) PTFE filament is considered to have a density of 1.95 g/cm³ or greater. As the density of the filament is reduced, such as disclosed in, for example, U.S. Pat. No. 7,060,354 to Baillie, the towing process becomes more difficult due to the softening characteristic of expanded PTFE possessing a density less than 1.9 g/cm³, and in some embodiments less than 1 g/cm³. A filament with higher break-strength is required to survive the high tensions needed during the fibrillation process. An object of the present is to provide a yarn incorporating ePTFE staple fiber having a density of about 1.9 g/cm³ or less.

To render the PTFE and ePTFE more dimensionally suitable for a carding process, the titer of the filament is reduced using a process known as fibrillation or towing. The towing of ePTFE filament is disclosed in U.S. Pat. No. 5,765,576 to Dolan, which is herein incorporated by reference in its entirety. The towing process may subject a significant amount of stress to the filament as the filament is sheared especially when the titer per filament is desired to be less the 7 denier per filament.

In certain embodiments, the fluoropolymer staple fibers may have a denier per filament (dpf) of less than about 60 and alternatively less than 15. In other embodiments, the fluoropolymer can have a dpf of less than 55 or less than 50 or less than 45 or less than 40 or less than 35 or less than 30 or less than 29 or less than 28 or less than 27 or less than 26 or less than 25 or less than 24 or less than 23 or less than 22 or less than 21 or less than 20 or less than 19 or less than 18 or less than 17 or less than 16, or less than 15. The lower limit for the dpf of the fluoropolymer staple fiber is not particularly important provided that the ratio of the average caliper diameter of the fluoropolymer staple fiber to the non-fluoropolymer staple fiber in the yarn is 1.2 or greater. The ratio of the average caliper diameters (fluoropolymer staple to non-fluoropolymer staple) can be at least 1.2. Depending on the staple fibers in the yarn, once the ratio of the average caliper diameters gets too large, for example, larger than 20, or larger than 30 or larger than 40, then the yarn becomes relatively weaker. Therefore, in some embodiments, the ratio of the average caliper diameters is less than about 30 or less than 20. In some embodiments, the ratio is 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0, 5.2, 5.4, 5.6, 5.8, 6.0, 6.2, 6.4, 6.6, 6.8, 7.0, 7.2, 7.4, 7.6, 7.8, 8.0, 8.2, 8.4, 8.6, 8.8, 9.0, 9.2, 9.4, 9.6, 9.8, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 16, 17, 18, 19, 20 or any value in between those listed numbers.

For incorporation of the fluoropolymer staple fiber into a short staple system (also known as the cotton carding process), the staple can have a length of less than 77 millimeters (mm), or less than 66 mm, or less than 58 mm, or less than 48 mm, or less than 38 mm, or less than 29 mm. For incorporation of the fluoropolymer staple fiber into a long staple system (also known as the wool carding process), the staple can have a length of less than 200 millimeters (mm), or less than 175 mm, or less than 150 mm, or less than 125 mm, or less than 100 mm, or less than 75 mm. In some embodiments, the length of the fluoropolymer staple fiber, for example, an ePTFE staple fiber can be in the range of from 25.4 mm (1 inch) to 31.75 mm (1.25 inches). In some embodiments, the fluoropolymer staple fiber can have a substantially rectangular cross-section. In general, the fluoropolymer staple fiber should have a length of greater than about 10 mm. Fluoropolymer staple fibers having a length of less than 5 mm can be difficult to form into a yarn.

Yarns of the present disclosure also comprise a non-fluoropolymer staple fiber. The non-fluoropolymer staple fibers can be one or more synthetic staple fibers, one or more natural fibers or a combination thereof. Suitable non-fluoropolymer staple fibers can include one or more of, for example, wool, cotton, silk, flax, hemp, hair from various animals, angora, sisal, raymie, acrylic, polyester, polyamide, polyaramid, polyurethane, acetate, rayon, polybenzimidazole, polybenzoxazole, lyocell, modacrylic, polyvinylidene chloride, carbon, glass, cellulose, cellulose acetate, cellulose esters, elastic fibers or a combination thereof. Suitable polyester staple fibers can include, for example, polyethylene terephthalate, polytrimethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate or a combination thereof. Natural fibers, for example, hair or fur from animals, cotton are typically used without further shortening of their length, although the fibers can be shortened, if desired, for example, silk fibers are typically long and can be cut to the desired staple length. Synthetic staple fibers are typically produced according to known techniques, for example, by extruding one or more filaments followed by chopping to the desired staple length. In some embodiments, the non-fluoropolymers comprise on or more staple diameters. Any of the additives discussed above can be added to the non-fluoropolymer fiber (or filaments) in order to produce the desired properties.

The non-fluoropolymer staple fibers can be of various lengths, generally, less than 200 millimeters (mm), or less than 175 mm, or less than 150 mm, or less than 125 mm, or less than 100 mm, or less than 75 mm. The denier of the synthetic non-fluoropolymer staple fibers can be smaller than that of the fluoropolymer staple fiber denier. In some embodiments, the denier of the synthetic non-fluoropolymer staple fiber can be greater than or equal to 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 0.8, 1.9 or 2.0. The titer of the natural fibers such as cotton and wool ranges between 0.7 to 2.3 denier for Upland cotton and 2 to 16 denier for sheep wool. In some embodiments, one or more non-fluoropolymer staple fibers can be used, each staple fiber independently having its own denier and thus each of the non-fluoropolymer staple fibers having one or more average caliper diameters. In some embodiments, the non-fluoropolymer staple fiber can comprise one or more polymers, for example, two individual but different polymer staple fibers or a bicomponent staple fiber produced from both polyester and polyamide. In other embodiments, the non-fluoropolymer staple fiber can comprise one or more natural fibers. In further embodiments, the non-fluoropolymer staple fiber is a polyester staple fiber, a polyamide staple fiber or a combination thereof. In the case of multiple non-fluoropolymer staple fibers being used, the average caliper diameter of the non-fluoropolymer staple fibers is the average of the caliper diameters, weighted for the amount (as a weight percentage) of each of the non-fluoropolymer staple fibers in the non-fluoropolymer staple fiber mixture.

In further embodiments, the yarn may further comprise one or more continuous filaments. The filaments are typically used as a core, around which the fluoropolymer staple fibers and the non-fluoropolymer staple fibers are wound. Core spun yarn process are known in the art and any of those processes can be used to form a core spun yarn having both fluoropolymer staple fibers and non-fluoropolymer staple fibers. If present, the filament can be an elastic filament, for example, elastane, spandex or LYCRA®; or a non-elastic filament, for example, a polyester or polyamide filament.

In certain embodiments, the yarns may be produced according to known processes, for example, processes which include spun yarn, open-end or rotor spinning, and air-jet or air-vortex spinning processes. The spun yarn process utilizes carding, drawing, roving and spinning. The opened-end or rotor spinning process takes staple fiber directly into spinning by-passing the need for roving the fiber. The fiber is fed into a high speed rotating reservoir where it is mixed and entangled together. Air-vortex spinning is similar to the opened-end process by converting staple fiber directly into a yarn by-passing the card. The fiber is mixed or entangled in a stationary tube using turbulent air. Prior to yarn formation, and if desired, one or more of the staple fibers can be optionally crimped using standard crimping operations such as the stuffing box method or geared nip roller method. The yarns of the present disclosure may include fluoropolymer staple fibers combined with natural staple fibers, synthetic staple fibers or both natural and synthetic staple fibers. In some embodiments, the yarns may include greater than 1 percent by weight fluoropolymer staple fibers to 100 percent by weight of fluoropolymer staple fibers (based on the total weight of the yarn) using typical carding, drawing and spinning methods. In other embodiments, the yarns can comprise in the range of from 1 percent by weight of the fluoropolymer staple fibers to less than 100 percent by weight of the fluoropolymer staple fibers. In still further embodiments, the yarns can comprise in the range of from 2 to 75 percent by weight or from 2 to 50 percent by weight or from 2 to 40 percent by weight or from 3 to 35 percent by weight of the fluoropolymer staple fibers, based on the total weight of the yarn. In some embodiments, the yarn comprises a fluoropolymer staple fiber and the amount of the fluoropolymer staple fiber is less than 35 percent by weight, based on the total weight of the yarn. In some embodiments, the fluoropolymer staple fiber is relatively evenly distributed within the yarn, for example, when the yarn is viewed as a cross section. In another embodiment, the disclosed yarns have a cross-section, perpendicular to the length of the yarn, that has an inner region, an outer region and a perimeter. The plurality of fluoropolymer staple fibers can be oriented primarily in the outer region of the cross-section and at least a portion of the fluoropolymer staple fibers extend outwardly beyond the yarn perimeter. In some embodiments, the at least a portion of the fluoropolymer staple fibers that extend outwardly beyond the yarn perimeter are the ends of the fluoropolymer staple fibers. Assuming that a yarn is approximately circular in cross-section, the phrase “inner region” of the yarn means the portion of the yarn that extends from the center of the yarn to the midpoint of the radius. The “outer region” of the yarn is the region that extends from the midpoint of the radius to the perimeter of the yarn.

Finishes such as antistatic and cohesion enhancing material can be applied to the fluoropolymer staple fiber and/or to the non-fluoropolymer staple fiber to increase efficiencies to the carding, drawing and spinning operations of the yarn formation process. In certain embodiments, the fluoropolymer staple fiber, for example, expanded PTFE, has a porosity where the finishes are able to reside, unlike full density PTFE staple fibers which have no pores. Additionally, one or more additives can be added to the yarn in order to enhance the properties of the yarn. For example, in some embodiments, the yarn can contain at least one of an antistatic component, a cohesion component, a wax, antimicrobial material, fragrance, antimildew agent, insect repellants, cooling agents, heating agents, analgesics, oleophobics, oleophilics, flame retardant materials, thermal insulates, color, signature identification markers, UV absorbers, light reflecting materials or a combination thereof.

Several advantages have been found through the disclosed with respect to the disclosed yarns. It was surprisingly found that despite the presence of the fluoropolymer staple fiber, which are typically hydrophobic materials and would therefore be expected to repel water, the disclosed yarns and articles produced from the yarns wet at a similar rate when compared to the same yarn or article produced without the fluoropolymer staple fibers. Even more surprisingly, the yarns and the articles produced from the yarns also dried faster when compared to the same yarn or article produced without the fluoropolymer staple fibers. Second, despite having relatively large caliper diameter fluoropolymer staple fibers, the disclosed yarns and fabrics produced from the yarns are soft, durable, quick drying and have excellent hand. This is counter to the trend in the art of yarns, especially for apparel yarns which has been to produce lower and lower denier fibers, i.e., for a particular fiber, a lower denier is directly related to lower caliper diameters. Yarns having low denier fibers produce fabrics that are soft and have excellent hand. It is surprising to produce yarns and fabrics having excellent hand, with the addition of relatively large fluoropolymer staple fibers, that is, a larger average caliper diameter when compared to the non-fluoropolymer staple fibers. Another surprising result is shown using the expanded PTFE fiber blended with wool. The hairiness was minimized using the expanded PTFE fiber compared to full density ePTFE fiber in wool.

Characterizing the fiber as an ideal cylinder of length L and radius r, both expressed in the units of cm the surface area can be shown in the following manner:

Volume = π Lr² ${Density} = \frac{{titer}*\left( {{unit}\mspace{14mu} {length}} \right)}{Volume}$

where unit length=9×10⁵ cm for titer expressed in denier or 1×10⁶ cm for titer expressed in dtex, and volume expressed in cm³.

Surface Area=2πrL+2πr ²

Showing density (ρ) in g/cm³ as a function of titer in dtex, L and r in cm:

$\rho = \frac{{titer} \times 10^{6}}{\pi \; L\; r^{2}}$ ${{or}\mspace{14mu} \pi \; r^{2}} = {{\frac{{titer} \times 10^{6}}{L\; \rho}\mspace{14mu} {and}\mspace{14mu} \pi \; L\; r} = \frac{{titer} \times 10^{6}}{r\; \rho}}$

Showing surface area as a function of density (ρ), r, and titer

${{Surface}\mspace{14mu} {Area}} = {{{2\; \pi \; r\; L} + \mspace{2mu} {2\; \pi \; r^{2}}} = {{\frac{2\left( {{titer} \times 10^{6}} \right)}{\rho \; r} + \frac{2\left( {{titer} \times 10^{6}} \right)}{\rho \; L}} = {2\; \frac{{titer} \times 10^{6}}{\rho}\left( {\frac{1}{r} + \frac{1}{L}} \right)}}}$

For a constant length L=1 cm,

${{Surface}\mspace{14mu} {Area}} = {2\; \frac{{titer} \times 10^{6}}{\rho}\left( {\frac{1}{r} + 1} \right)}$

Therefore, as density decreases for a given titer, and r is constant, the surface area increases. An interesting and useful result of the above derivation relating to expanded PTFE as shown in U.S. Pat. No. 3,953,566 to Gore, the cross-sectional area of the expanded PTFE element remains substantially constant as the density of the element decreases due to increasing expansion ratio. In the above derivation, r is thus held constant as the density of ePTFE changes resulting in the relationship for surface area of the ePTFE fiber a function of its titer and density. Therefore, it can be seen that for a given titer, as the density of expanded PTFE is decreased, the surface area and the benefits of the surface area (e.g., decreasing friction between neighboring elements, and the lowering of surface energy, etc.) are increased.

Yarns according to the disclosure can be used to produce articles, for example, textiles using any known method for producing textiles from yarns. The textile can be produced via known knitting, weaving or nonwoven methods to produce knit textiles, woven textiles, nonwoven textiles or fleece textiles. Suitable examples of textile making methods can include, for example, warp knitting, weft knitting, circular knitting, flatbed knitting, seamless knitting, broad loom, narrow width weaving, belting, rapier weaving, shuttle weaving, air jet weaving, water jet weaving, projectile loom weaving, and jacquard weaving. Suitable examples of nonwoven methods can include, for example, needle punching, hydroentanglement, wet-laid and meltblown. Textiles can be produced using one or more yarns of the present disclosure or the textiles can comprise the disclosed yarns and one or more other yarns. Another object of the present invention is to provide an expanded PTFE fiber for yarn blends which yield the woven or knitted textile with improved drape or hand.

The present disclosure also relates to a method for reducing the drying time of an article, wherein the method comprises producing an article, wherein the article comprises a yarn comprising; i) a plurality of fluoropolymer staple fibers with an average caliper diameter of at least 15 microns, and ii) a plurality of non-fluoropolymer staple fibers, wherein the ratio of the average caliper diameter of the fluoropolymer staple fibers to the non-fluoropolymer staple fibers in the yarn is 1.2 or greater; and wherein the drying time is reduced when compared to a similar article produced from a yarn consisting of ii) the plurality of the non-fluoropolymer staple fibers.

The present disclosure also relates to a method for reducing the water pick up of an article, wherein the method comprises producing an article, wherein the article comprises a yarn comprising; i) a plurality of fluoropolymer staple fibers with an average caliper diameter of at least 15 microns, and ii) a plurality of non-fluoropolymer staple fibers, wherein the ratio of the average caliper diameter of the fluoropolymer staple fibers to the non-fluoropolymer staple fibers in the yarn is 1.2 or greater; and wherein the drying time is reduced when compared to a similar article produced from a yarn consisting of ii) the plurality of the non-fluoropolymer staple fibers.

Measurements and Test Methods Filament Titer

Titer of the filament is measured by measuring the mass in grams of a 90 meter length of filament and multiplying the result by 100. The mass is measured using a mass balance having a precision of at least 0.1 grams. The length is measured using a skein reel having length detection to a precision of at least 5 cm. A typical electric yarn skein reel such as model ILE-1-SKRM is available from ILE Company located in Charlotte, N.C. 28222. Three measurements are taken and averaged.

Denier Per Fiber

Denier per fiber (dpf) is measured by splaying a 500 mm length section of the towed filament over a flat surface having a dark background such as black or navy blue in color. The filament is evenly opened as it is splayed and lying on top of the measuring board of dark color. A substantially flat meter stick is laid over the splayed tow filament such that is covers the entire width of the filament. Any fiber shown next to one side of the meter stick is counted and the total number is summed. The sum is divided by the titer of the filament resulting in the denier per fiber. One test per sample is performed.

Filament Thickness

Thickness of the tape and monofilament is measured using a snap gauge having a precision of 0.1 mm. The snap gauge is outfitted with 15 mm diameter flat disk pads. Five measurements are taken per sample and averaged.

Filament Width

Filament width was measured in a conventional manner utilizing an eye loop of 10× magnification having gradations to the nearest 0.1 mm. Three measurements were taken and averaged to determine the width to the nearest 0.05 mm.

Filament Break Strength

The filament break strength was the measurement of the maximum load needed to break (rupture) the filament. The break strength was measured by a tensile tester, such available from the Instron Machine Company located in Canton, Mass. The Instron™ machine was outfitted with fiber (horn type) jaws that are suitable for securing filaments and strand elements during the measurement of tensile loading. The cross-head speed of the tensile tester was 25.4 cm per minute. The gauge length was 25.4 cm. Five measurements of each filament type were taken with the average reported in units of Newtons.

Filament Tenacity

Filament tenacity is the break strength of the filament normalized to its titer (weight per length of the filament). Filament tenacity was calculated using the following formula:

Filament tenacity (cN/dtex)=Filament break strength (cN)/100 Filament titer (dtex)

Filament Density

Filament density was calculated utilizing the previously measured filament titer (weight per length), filament width and filament thickness using the following formula:

Filament Density (g/cm³)=Filament titer (dtex)/Filament Width (mm)/Filament Thickness (mm)/10,000

Average Caliper Diameter (Feret Diameter) of a Fiber

The average caliper diameter can generally be described as the average largest diameter measurement of a staple fiber in a yarn, which is interchangeably referred to as the Feret diameter. The average can be determined by cutting a yarn to reveal the cross section. The cross section is then analyzed, looking for at least three fluoropolymer staple fibers (more than one cross section may have to be analyzed). The yarn cross-sections are then subjected to microscopy, for example, optical or electron microscopy. The maximum cross-sectional distance is measured for each of three fluoropolymer fibers in the yarn. The average of those three lengths is then determined. The same procedure is then used to determine the average caliper diameter of the non-fluoropolymer fiber. At least three fibers of each type are measured and the average of the at least three fibers is reported as the average caliper diameter. In some embodiments, the average caliper diameter is a measured value using the procedure given above. Alternatively, the exterior of the yarn can be examined using optical microscopy and visually identifying the fluoropolymer and non-fluoropolymer staple fibers. The maximum widths of the fibers can be measured for three individual staple fibers of each type of staple fiber in the yarn and the average can be calculated. In other embodiments, the average caliper diameter is a calculated value, based on the assumption that the cross-section of the fluoropolymer fiber is round, and based on the formula given below. In the present disclosure, if the value is a calculated value, the value will be listed as “calculated” and the average caliper diameter will be given as “at least” a certain value.

The caliper diameter has units of micrometers (10⁻⁶ meter) and can also be determined, based on a generally round fiber cross-section assumption, for the calculation using the following equation:

${{Feret}\mspace{14mu} {Diameter}\mspace{14mu} \left( {\mu \; m} \right)} = {10000*\sqrt{\frac{DENIER}{225000*\rho*\pi}}}$

Where:

Denier is in g/9000 m Density is g/cm3 Diameter is in microns

Thermal Protective Performance (TPP)

Thermal Protective Performance (TPP) is related to the time to record second degree burn, and materials having higher TPP values are considered to offer better burn protection. In one embodiment, a method is described for improving the thermal performance protection (TPP) of a thermally stable textile and thereby forming a thermally protective material.

TPP Test Method

Multiple test specimens (6×6 in.) of the materials were prepared for testing. Thermal resistance was measured using the CSI Thermal Protective Performance (TPP) Tester according to NFPA 1971 Standard on Protective Ensemble for Structural Fire Fighting; Section 6-10 of the 2000 edition.

Individual materials were tested with a ¼″ spacer. Also, ensembles or assemblies with multiple materials lay-up were tested in contact configuration as specified by the test method.

Vertical Flame Test

Textile material samples were tested in accordance with ASTM D6413 test standard. Samples were exposed to flame for 12-seconds, After-flame time was averaged for 3 samples. Textiles with after-flame of greater than 2 seconds were considered as flammable; textiles with an after-flame of less than or equal to about 2 seconds were considered flame resistant.

Hand Via Handle-o-Meter Test

AATCC (American Association of Textile Chemists and Colorist) Evaluation Procedure 5 is used to measure the effect of selective compression on the hand of ePTFE laminates by using a bending test. The equipment used is a Handle-O-Meter, Model 211-5-10 manufactured by Thwing/Albert Instrument Co. Philadelphia, Pa. Ten test specimens of the desired material are cut to about 4 inch×about 4 inch squares. Five are cut in the fill direction. Five are cut in the warp direction. AH specimens are then conditioned at 70±2° F., 65±2% Relative Humidity (hereinafter “RH”) for about 4 hours prior to testing. An about 1000 gram beam is used to push the test specimens though an about ¼″ slot. The resistance force, related to the bending stiffness of the fabric, is measured and displayed digitally. The peak force is recorded and used to compare samples. The samples are then averaged tested for hand using the Handle-O-Meter.

Elmerdorf Tear Test

Tear test is per ASTM D1424.

Yarn Hairiness Score

Suspend a 500 mm yarn sample from a ring stand affixing one end to a ring stand and a 25 g weight on the second distal end. Permit the yarn to freely untwist to a steady resting state. Near or at the middle of the yarn mark a line using a marker pen and place a second line or mark 25 mm above the first line. Visually count the number of the fibers extending more than 0.5 mm from the yarn over the 25 mm marked section and grade the yarn for hairiness using the reference Table 1 below. Perform the test on 7 yarns per sample and average Hairiness Score and round upwards to next integer for final result.

TABLE 1 Hairiness Scoring Number of ends extending out from yarn Hairiness Score None 1 Less than 3 2 Less than 7 3 Less than 10 4 More than 11 5

Martindale Abrasion

Abrasion resistance was measured using a Martindale Abrasion tester, model 1305, available from James Heal, Halifax, United Kingdom. The samples were tested according to the standard operating procedures, the test abrading cloth was the wool standard. Only the weight of the fixture plate is used as the applied weight. The number of cycles before hole generation in the test candidate are counted. Five samples per test candidate are performed and the results averaged.

EXAMPLES Example 1

An expanded PTFE fiber having the following properties was obtained: Width: 18.4 mm; Thickness: 0.089 mm, Titer: 2224 tex; Density: 1.34 g/cm³; Tensile strength: 61.2 kilogram (kg); Tenacity: 27.5 g/tex. The fiber was passed perpendicularly over a fibrillation (or towing roller) roller containing pin bars parallel to the axis of rotation. The pin bars, available from the Burkhardt Company (Switzerland), having 15 pins per cm, each pin 1.2 mm in length. The fiber passing over the fibrillation roller was positioned such that at least 3 pin bars were in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 2.8 times faster. The resulting denier per fiber (dpf) was between 15 and 30 denier. The average caliper diameter was 40-56 microns.

Example 2

An expanded PTFE fiber having the following properties was obtained: Width: 10.3 mm; Thickness: 0.13 mm; Titer: 2000 tex; Density: 1.55 g/cm³; Tensile strength: 36.58 kg; Tenacity: 18.3 g/tex.

The fiber was passed perpendicularly over a series of two fibrillation rollers containing pin bars parallel to the axis of rotation. The pin bars, available from the Burkhardt Company (Switzerland), the first roller having 15 pins per cm such that at least 3 pin bars were in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 1.3 times faster. The pin projection length was 2 mm. The second fibrillation roller having 50 pins per cm such that at least 3 pin bars were in contact with the fiber and the relative velocity between one pin bar to the velocity of the filament was 2.3 times faster. The pin projection length was 2 mm. The speed ratio difference between the nip roller assembly feeding the filament to the first fibrillation roller to the nip assembly roller was 5% faster (or with sufficient tension so that the pins penetrate the material). The speed ratio difference between the nip roller assembly feeding the filament to the second fibrillation roller to the nip assembly roller was 4% faster. The resulting tow had a denier per fiber (dpf) of 7.

The tow fiber was crimped using the stuffing box style crimper model CL-21 available from the DM& E Company located in Shelby, N.C. The crimp was between 6 and 20 crimps per inch. The crimped tow filament was cut into a staple fiber using a staple cutter model number series 20 staple cutter available from the DM &E Company located in Shelby, N.C. The staple length was 70 mm (uncrimped length). Tow filament strands were combined such that the bulk titer of the combined yarn bundle was between 75,000 and 120,000 denier entering the crimper and staple cutter. Subsequently, the staple was opened using air opener where the staple travels through a 254 mm diameter conduit, 3 meters long in a turbulent air stream flowing at a volume of 300 standard cubic feet per minute. The rate of staple entering the airstream was 500 g per minute and the ratio of staple mass to air was about 60 g/m³.

Blending

Australian grade #1 Merino wool and ePTFE staple fibers of this example were weighed and blended by hand just before processing through a mechanical air tower blender. The ePTFE fiber weight ratio to wool was 10%. Sizing was not used to treat the wool or ePTFE staple. The wool was clean of debris and lanolin.

Carding

A woolen card (Mackie International, Ireland) was used to create sliver from the blended staple. Staple material was manually placed into the hopper of the card where a pick opener was utilized to transfer the material onto a conveyor belt that fed the card's main cylinder and working rollers. Autoleveling was not used during carding. Sliver exited the card through a 2.5-in diameter trumpet before being coiled into sliver cans. The sliver cans were manually transported to the spinning room floor.

Spinning

Doubling and drawing was achieved using pin servo-drawer model M-3730 from the Warner & Swasey Company. The doubling sequence was six slivers formed into one sliver and drafted at a ratio of 6:1. The second drawing stage combined three slivers together using the same servo drawer but set at a ratio of 3:1. The sliver was then placed through a pin drafter model M-3680 from the Warner & Swasey Company using a draft ratio of 3:1. The total draft of the sliver was 6×3×3=54. Autoleveling was used during all pin drawing and drafting stages. A roving step was not used.

A back draft in the range of 1.5:1-2:1 was used during yarn spinning. The main draft was an apron-style design. The yarn received a final draft at a ratio of 20:1 from the main draft. A twist of 7.5 twist per inch (TPI) in the S direction was placed in the yarn. The resulting weight was 15 worsted count or 531 denier, single-ply yarn. The average caliper diameter of the PTFE fiber was 61.7 micrometers, and the average caliper diameter of the wool was 18.1 micrometers.

Example 3

A coherent ePTFE fiber (that is, an ePTFE fiber tow) having a denier per fiber of about 7 dpf and a density=1.6 g/cm³ was produced. Subsequently, the ePTFE fiber was crimped, cut and blended with Australian grade #1 Merino grade 1 wool at a ratio of 20% by mass of PTFE to wool to produce a blended single ply yarn at titer=531 denier in the same manner as in Example 2. The calculated average caliper diameter of the PTFE fiber was at least 25, and the average caliper diameter of the wool was 18.

Example 4

A coherent ePTFE fiber having a denier per fiber of about 7 and a density=1.6 g/cm³ was produced. Subsequently, the ePTFE fiber was crimped, cut and blended with Australian grade #1 Merino grade 1 wool at a ratio of 30% by mass of PTFE to wool to produce a blended single ply yarn having a titer of 531 denier in the same manner as in Example 2. The calculated average caliper diameter of the PTFE fiber was at least 25, and the average caliper diameter of the wool was 18.

Comparative Example 5

A commercially available PTFE staple fiber from the Ling Qiao E.P.E.W. Company, Ltd. Located in China, Part number JUSF-W-1 was blended with Australian grade #1 Merino wool and formed into a yarn in the same manner as Example 2. The PTFE fiber had a denier per fiber of about 15 dpf and a density=2.1 g/cm³. The PTFE fiber and Merino wool were blended at a ratio of 10% by mass of PTFE to wool resulting in a blended single ply yarn having a titer of 531 denier. The average caliper diameter of the PTFE fiber was 44.3 micrometers, and the average caliper diameter of the wool was 19.1 micrometers.

Comparative Example 6

A commercially available PTFE staple fiber from the Ling Qiao E.P.E.W. Company, Ltd. Located in China, Part number JUSF-W-1 was blended with Australian grade #1 Merino wool and formed into a yarn in the same manner as Example 2. The PTFE fiber had a denier per fiber of about 15 and a density=2.1 g/cm³. The PTFE fiber and Merino wool were blended at a ratio of 20% by mass of PTFE to wool resulting in a blended single ply yarn having a titer of 531 denier. The calculated average caliper diameter of the PTFE fiber was at least 31, and the average caliper diameter of the wool was 18.

Comparative Example 7

A commercially available PTFE staple fiber from the Ling Qiao E.P.E.W. Company, Ltd. Located in China, Part number JUSF-W-1 was blended with Australian grade #1 Merino wool and formed into a yarn in the same manner as Example 2. The PTFE fiber had a denier per fiber of about 15 dpf and a density=2.1 g/cm³. The PTFE fiber and Merino wool were blended at a ratio of 30% by mass of PTFE to wool resulting in a blended single ply yarn having a titer of 531 denier. The calculated average caliper diameter of the PTFE fiber was at least 31, and the average caliper diameter of the wool was 18.

Reference Comparative Example 8

Commercially available Australian grade #1 Merino wool was produced into a spun yarn in the same manner as Example 2. The resulting 100% wool spun yarn was a single ply yarn having a titer of about 531 denier.

The number of fibers extending from the yarns of examples 2 to 7 was scored using a hairiness score. The yarns containing the inventive ePTFE fiber having a density of 1.6 g/cc appeared less hairy than the yarns containing the commercially available PTFE fiber. Moreover, as the PTFE content increased, the hairiness was decreased. FIG. 1 shows the hairiness score as a function of PTFE content in the wool yarn and as a function of the density of the PTFE fiber.

The increased strength of the expanded PTFE staple compared to non-expanded PTFE staple fiber is shown in Table 2. Table 2 is a stress versus strain graph of ePTFE staple having a density of 1.6 g/cm³ and a fiber titer of 15 dpf described in Example 1 and the commercially available PTFE staple fiber possessing a density of 2.1 g/cm³ and a fiber titer of 15 dpf.

Example 9

A coherent ePTFE fiber having a denier per fiber of 7 and a density=1.6 g/cm³ was produced. Subsequently, the ePTFE fiber was crimped, cut and blended with meta-aramid at ratio of 20% by mass of PTFE to meta-aramid to produce a blended single ply yarn at titer=450 denier in the same manner as in Example 2.. The meta aramid was obtained from the Chemours Company, Wilmington, Del. The staple length of the meta-aramid was 76 mm and had no finish applied and was crimped. The average caliper diameter of the PTFE fiber was 117.6 micrometers, and the average caliper diameter of the meta-aramid was 13.3 micrometers.

Comparative Example 10

A commercially available PTFE staple fiber from the Ling Qiao E.P.E.W. Company, Ltd. Located in China, Part number JUSF-W-1 was blended with meta-aramid and formed into a yarn in the same manner as Example 2. The PTFE fiber had a denier per fiber of about 15 dpf and a density=2.1 g/cm³ and an average caliper diameter of 32 microns. The meta-aramid was obtained from the Chemours Company, Wilmington, Del. The staple length of the meta-aramid was 76 mm and had no finish applied and was crimped. The PTFE fiber and meta-aramid were blended at a ratio of 20% by mass of PTFE to wool resulting in a blended single ply yarn having a titer of 450 denier.

Comparative Example 11

A commercially available meta-aramid staple fiber was obtained from the Chemours Company, Wilmington, Del. and produced into a spun yarn in the same manner as Example 2. The staple length of the meta-aramid was 76 mm and had no finish applied and was crimped. The resulting spun yarn produced was a single ply yarn having a titer of 450 denier.

The yarns from Examples 9, 10 and 11 were woven in into cloths using a 4 shaft rapier loom available from the CCI, Inc. Company, Tapei, Taiwan. The weave design was a plain weave producing cloths of weights having 75 ends per inch (epi), 70 picks per inch (ppi) and approximately 7 oz per yard² (about 237 grams per meter²). Table 3 contains the results of vertical flame test per ASTM D6413. Two runs of each sample were performed and the average of the two runs was calculated. Table 4 contains the results of the hand and Elmendorf tear tests.

TABLE 3 Vertical Flame Test; plain weave 75 epi × 70 ppi, 7.0 oz/yd² Sample Item # Direction Property 1 2 Average Comparative Warp After 0.5 0.7 0.6 Example 10 Flame(sec) Comparative Warp After Glow 61.0 17.0 39.0 Example 10 (sec) Comparative Warp Melt/Drip No No No Example 10 drip drip drip Comparative Warp Char Length 2.8 3.0 2.9 Example 10 (cm) Comparative Fill After 0.0 0.0 0.0 Example 10 Flame(sec) Comparative Fill After Glow 22.0 17.0 19.5 Example 10 (sec) Comparative Fill Melt/Drip No No No Example 10 drip drip drip Comparative Fill Char Length 3.2 3.0 3.1 Example 10 (cm) Inventive Warp After 0.6 0.5 0.5 Example 9 Flame(sec) Inventive Warp After Glow 15.0 17.0 16.0 Example 9 (sec) Inventive Warp Melt/Drip No No No Example 9 drip drip drip Inventive Warp Char Length 2.3 2.8 2.6 Example 9 (cm) Inventive Fill After 0.0 0.0 0.0 Example 9 Flame(sec) Inventive Fill After Glow 20.0 17.0 18.5 Example 9 (sec) Inventive Fill Melt/Drip No No No Example 9 drip drip drip Inventive Fill Char Length 3.0 3.2 3.1 Example 9 (cm) Reference Warp After 0.0 0.0 0.0 Example 11 Flame(sec) Reference Warp After Glow 17.0 28.0 22.5 Example 11 (sec) Reference Warp Melt/Drip No No No Example 11 drip drip drip Reference Warp Char Length 2.8 2.9 2.9 Example 11 (cm) Reference Fill After 0.0 0.0 0.0 Example 11 Flame(sec) Reference Fill After Glow 23.0 29.0 26.0 Example 11 (sec) Reference Fill Melt/Drip No No No Example 11 drip drip drip Reference Fill Char Length 2.7 3.1 2.9 Example 11 (cm)

TABLE 4 Hand and Elmendorf tear results Example # sample details hand avg Hand Elmendorf Reference 100% Metaaramid 272 271 Did not tear Example 11 268 274 Inventive ePTFE/Metaaramid 170 175 Did not tear Example 9 178 176

Example 12

A coherent ePTFE (tow) filament was produced in the same manner as in Example 1 and having a density of 0.85 grams/cm³. Subsequently, the filament was passed perpendicularly over a series of two fibrillation rollers containing pin bars parallel to the axis of rotation. The pin bars, available for the Burkhardt Company located in Switzerland, the first roller having 30 pins per cm such that at least 5 pin bars were in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 1.4 times faster. The second fibrillation roller having 50 pins per cm such that at least 3 pin bars are in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 2.5 times faster. The speed ratio difference between the nip roller assembly feeding the filament to the first fibrillation roller to the nip assembly roller was 5% faster. The speed ratio difference between the nip roller assembly feeding the filament to the second fibrillation roller to the nip assembly roller was 4% faster. The higher relative rotational speeds of the nip roller assemblies exiting the fibrillation roller to the nip assembly rollers feeding the fibrillation roller creates tension in the filament. The induced tension helps to maintain the filament in contact with the fibrillation roller. The resulting denier per fiber (dpf) was about 7.

The tow filament was crimped using the stuffing box style crimper model CL-21 available from the DM& E Company located in Shelby, N.C. The crimp was between 6 and 20 crimps per inch.

The crimped tow filament was cut into a staple fiber using a staple cutter model number series 20 staple cutter available from the DM &E Company located in Shelby, N.C. The staple length was 76 mm (uncrimped length). Tow filament strands were combined such that the bulk titer of the combined yarn bundle was between 75,000 and 100,000 denier entering the crimper and staple cutter. Subsequently, the staple was opened using air opener where the staple travels through a 254 mm diameter conduit, 3 meters long in a turbulent air stream flowing at a volume of 300 standard cubic feet per minute. The rate of staple entering the airstream was 500 g per minute hence the ratio of staple mass to air was about 60 g/m³.

Blending

Meta-aramid and ePTFE staple materials were weighed and blended by hand prior to entering a mechanical staple blender. The ePTFE fiber weight ratio to meta-aramid was 7.5%. A card sizing agent part number Selbana UN available from Pulcra Chemicals located in Munich, Germany was applied to the ePTFE and meta-aramid staple. The sizing agent was prepared using one part Selbana UN to six parts distilled water. The prepared sizing agent was applied using an amount of about 1% of the weight of the fiber. Hence for a total weight of the ePTFE and meta-aramid batch was 100 kg, 1 kg of sizing agent was applied to the blend prior to carding.

Carding

A woolen card obtained from the Mackie International Company, Ltd., located in Ireland was used to create sliver from the blended staple. Staple material was manually placed into the hopper of the card where a pick opener was utilized to transfer the material onto a conveyor belt that fed the card's main cylinder and working rollers. Autoleveling was used during carding. Sliver exited the card through a 2.5-in diameter trumpet before being coiled into sliver cans. The sliver cans were manually transported to the spinning room floor where the material was doubled and drawn.

Doubling and drawing was achieved using pin servo-drawer model M-3730 from the Warner & Swasey Company. The doubling sequence was six slivers formed into one sliver and drafted at a ratio of 6:1. The second drawing stage combined three slivers together using the same servo drawer but set at a ratio of 3:1. The sliver was then placed through a pin drafter model M-3680 from the Warner & Swasey Company using a draft ratio of 3:1. The total draft of the sliver was 6×3×3=54. Autoleveling was used during all pin drawing and drafting stages. A roving step was not necessary because the sliver's inherent tensile strength was sufficient to withstand the spinning operation.

A back draft in the range of 1.3:1-2:1 was used during yarn spinning. The main draft was an apron-style design. The yarn received a final draft at a ratio of 24:1 from the main draft. A twist of 8 twist per inch (TPI) in the S direction was placed in the yarn. The resulting titer was a 450 denier (500 dtex), single-ply yarn.

Example 13

A blended spun yarn was made same as in Example 12 except the blend ratio of ePTFE was 30% to meta-aramid.

Comparative Example 14

A reference spun yarn was made according to the same carding and spinning procedure described in Example 12 except no ePTFE staple was added. The resulting yarn had a titer of 450 denier (500 dtex) and was single ply.

The spun yarns produced in Examples 12, 13, and 14 were knitted into a 10 inch (254 mm) diameter knit using a 10 inch diameter circular knitting machine available from the Bentley Engineering Company, Ltd. Compound needles were used and eight supply packages fed the knitting machine using a simple lock stitch with a gauge of 24.

Two inch (508 mm) wide by 6 inch long (152 mm) test swatches were cut from the circular knitted tube structure. The swatches were oriented such that the 6 inch (152 mm) length cut length was in the wale direction of the knit.

A handle-o-meter was used to determine the hand of the knitted swathes. FIG. 2 is a graph of the hand results for Examples 12, 13, and 14 shown as Hand versus percent of inventive ePTFE staple blended with meta-aramid staple fiber.

The hand was improved by incorporating the lower density ePTFE staple fiber in the meta-aramid yarn.

Example 15

A coherent ePTFE (tow) filament was produced in the same manner as in Example 1 except that the density of the ePTFE was 0.85 grams/cm³. Subsequently, the filament was passed perpendicularly over a series of two fibrillation rollers containing pin bars parallel to the axis of rotation. The pin bars, available for the Burkhardt Company located in Switzerland, the first roller having 30 pins per cm such that at least 5 pin bars were in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 1.4 times faster. The second fibrillation roller having 50 pins per cm such that at least 3 pin bars are in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 2.5 times faster. The speed ratio difference between the nip roller assembly feeding the filament to the first fibrillation roller to the nip assembly roller was 5% faster. The speed ratio difference between the nip roller assembly feeding the filament to the second fibrillation roller to the nip assembly roller was 4% faster. The higher relative rotational speeds of the nip roller assemblies exiting the fibrillation roller to the nip assembly rollers feeding the fibrillation roller creates tension in the filament. The induced tension helps to maintain the filament in contact with the fibrillation roller. The resulting denier per fiber (dpf) was about 7.

The tow filament was crimped using the stuffing box style crimper model CL-21 available from the DM& E Company located in Shelby, N.C. The crimp was between 6 and 20 crimps per inch.

The crimped tow filament was cut into a staple fiber using a staple cutter model number series 20 staple cutter available from the DM&E Company located in Shelby, N.C. The staple length was 76 mm (uncrimped length). Tow filament strands were combined such that the bulk titer of the combined yarn bundle was between 75,000 and 100,000 denier entering the crimper and staple cutter. Subsequently, the staple was opened using air opener where the staple travels through a 254 mm diameter conduit, 3 meters long in a turbulent air stream flowing at a volume of 300 standard cubic feet per minute. The rate of staple entering the airstream was 500 g per minute hence the ratio of staple mass to air was about 60 g/m³.

Blending

Merino wool and ePTFE staple materials were weighed and blended by hand prior to entering a mechanical staple blender. The ePTFE fiber weight ratio to wool was 10%. A card sizing agent part number Selbana UN available from Pulcra Chemicals located in Munich, Germany was applied to the ePTFE and wool staple. The sizing agent was prepared using one part Selbana UN to six parts distilled water. The prepared sizing agent was applied using an amount of about 1% of the weight of the fiber. Hence for a total weight of the ePTFE and merino wool batch was 100 kg, 1 kg of sizing agent was applied to the blend prior to carding.

Carding

A woolen card or “long staple card” obtained from the Mackie International Company, Ltd., located in Ireland was used to create sliver from the blended staple. Staple material was manually placed into the hopper of the card where a pick opener was utilized to transfer the material onto a conveyor belt that fed the card's main cylinder and working rollers. Autoleveling was used during carding. Sliver exited the card through a 2.5-in diameter trumpet before being coiled into sliver cans. The sliver cans were manually transported to the spinning room floor where the material was doubled and drawn.

Doubling and drawing was achieved using pin servo-drawer model M-3730 from the Warner & Swasey Company. The doubling sequence was six slivers formed into one sliver and drafted at a ratio of 6:1. The second drawing stage combined three slivers together using the same servo drawer but set at a ratio of 3:1. The sliver was then placed through a pin drafter model M-3680 from the Warner & Swasey Company using a draft ratio of 3:1. The total draft of the sliver was 6×3×3=54. Autoleveling was used during all pin drawing and drafting stages. A roving step was not necessary because the sliver's inherent tensile strength was sufficient to withstand the spinning operation.

A back draft in the range of 1.3:1-2:1 was used during yarn spinning. The main draft was an apron-style design. The yarn received a final draft at a ratio of 24:1 from the main draft. A twist of 8 twist per inch (TPI) in the S direction was placed in the yarn. The resulting titer was a 550 denier (611 dtex), single-ply yarn.

Example 16

A blended spun yarn was made same as in Example 15 except the blend ratio of ePTFE was 30% to merino wool.

Comparative Example 17

A reference spun yarn was made according to the same carding and spinning procedure described in Example 15 except no ePTFE staple was added. The resulting yarn had a titer of 550 denier (611 dtex) and was single ply.

The spun yarns produced in Examples 15, 16, and 17 where knitted into a 10 inch (254 mm) diameter knit using a 10 inch diameter circular knitting machine available from the Bentley Engineering Company, Ltd. Compound needles were used and eight supply packages fed the knitting machine using a simple lock stitch with a gauge of 24.

Two inch (508 mm) wide by 6 inch long (152 mm) test swatches were cut from the circular knitted tube structure. The swatches were oriented such that the 6 inch (152 mm) length cut length was in the wale direction of the knit. A handle-o-meter was used to determine the hand of the knitted swathes. FIG. 4 is a graph of the hand results for Examples 15, 16, and 17. The hand for examples 15 and 16 relative to comparative Example 17 was improved by incorporating the lower density ePTFE staple fiber in the Merino wool.

Example 18

A coherent ePTFE (tow) filament was produced in the same manner as in Example 1 and having a density of 0.85 g/cm³. Subsequently, the filament was passed perpendicularly over a series of two fibrillation rollers containing pin bars parallel to the axis of rotation. The pin bars, available for the Burkhardt Company located in Switzerland, the first roller having 15 pins per cm such that at least 3 pin bars are in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 1.3 times faster. The pin projection length was 2 mm. The second fibrillation roller having 50 pins per cm such that at least 3 pin bars are in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 2.3 times faster. The pin projection length was 2 mm. The speed ratio difference between the nip roller assembly feeding the filament to the first fibrillation roller to the nip assembly roller was 5% faster. The speed ratio difference between the nip roller assembly feeding the filament to the second fibrillation roller to the nip assembly roller was 4% faster. The higher relative rotational speeds of the nip roller assemblies exiting the fibrillation roller to the nip assembly rollers feeding the fibrillation roller creates tension in the filament. The induced tension helps to maintain the filament in contact with the fibrillation roller. The resulting denier per fiber (dpf) was about 7.

The tow filament was crimped using the stuffing box style crimper model CL-21 available from the DM& E Company located in Shelby, N.C. The crimp was between 6 and 20 crimps per inch.

The crimped tow filament was cut into a staple fiber using a staple cutter model number series 20 staple cutter available from the DM &E Company located in Shelby, N.C. The staple length was 50 mm (uncrimped length). Tow filament strands were combined such that the bulk titer of the combined yarn bundle was between 75,000 and 120,000 denier entering the crimper and staple cutter. Subsequently, the staple was opened using air opener where the staple travels through a 254 mm diameter conduit, 3 meters long in a turbulent air stream flowing at a volume of 300 standard cubic feet per minute. The rate of staple entering the airstream was 500 g per minute hence the ratio of staple mass to air was about 60 g/m³. A card sizing agent part number Selbana UN available from Pulcra Chemicals located in Munich, Germany was applied to the ePTFE staple. The sizing agent was prepared using one part Selbana UN to six parts distilled water. The prepared sizing agent was applied using an atomizer spraying nozzle at an amount of about 1% of the weight of the ePTFE staple fiber.

Example 19

A three component spun yarn was made consisting of PBI (polybenzimidazole) staple fiber having a length of 50 mm and a titer of 1.2 dpf obtained from the Performance Products Company, Inc. located in Charlotte, N.C. and para-aramid staple having a length of 50 mm and a titer of 1.3 dpf obtained from E.I. DuPont Company, located in Wilmington, Del. and ePTFE staple fiber made in the same manner as Example 18. The staple fibers were weighed and blended by hand before processing through a mechanical blender. The ePTFE fiber weight content was 20%, the PBI weight content was 40% and the para-aramid weight content was 40%.

A cotton card (or short staple card) similar to model TC15 from the Trützschler Company, GmbH located in Germany was used to create sliver from the blended staple. The card wire utilizes flats as opposed to working rollers. The card wire is typically used for para-aramid staple. Staple material was conveyed automatically from the mechanical opener to the hopper of the card where a pick opener was utilized to transfer the material onto a conveyor belt that fed the card's main cylinder and flats. Autoleveling and nep prevention were used during carding. Sliver exited the card through a 50 mm diameter trumpets before being coiled into sliver cans. The sliver cans were manually transported to the spinning room floor.

Doubling and drawing was achieved using an auto leveler pin draw frame similar to model TD8 from the Trützschler Company, GmbH located in Germany. The doubling sequence was seven slivers formed into one sliver and drafted at a ratio of 7:1. The second drawing stage combined three slivers together using the same servo drawer but set at a ratio of 3:1. The sliver was then placed through a pin drafter set at a draft ratio of 3:1. The total draft of the sliver was 7×3×3=63. Autoleveling was used during all drafting stages.

A back draft in the range of 1.3:1 to 2:1 was used during yarn spinning. The main draft was an apron-style design. The yarn received a final draft at a ratio of 15:1 from the main draft. A twist of 26 twist per inch (TPI) in the S direction was placed in the yarn. The resulting weight was 12 cotton count or 446 denier (496 dtex), single-ply yarn.

Comparative Example 20

A two component spun yarn was made consisting of PBI (polybenzimidazole) staple fiber having a length of 50 mm and a titer of 1.2 dpf obtained from the Performance Products Company, Inc. located in Charlotte, N.C. and para-aramid staple having a length of 50 mm and a titer of 1.3 dpf obtained from E.I. DuPont Company in the same manner as Example 24 but without the ePTFE staple fiber. The PBI weight content was 40% and the para-aramid weight content was 60%.

The resulting yarn weight was 12 cotton count or 446 denier (496 dtex), single-ply yarn twisted at 26 TPI.

Example 21

The yarns formed in Example 19 were woven on a 4 harness rapier loom available from the Dornier Company, GmbH located in Lindau, Germany to form a plain weave at 43 epi×43 ppi and weighing 5.56 osy. The woven cloth was tested for abrasion using the standard Martindale test.

Comparative Example 22

The yarns formed in Comparative Example 20 were woven on a 4 harness rapier loom available from the Dornier Company, GmbH located in Lindau, Germany to form a plain weave at 43 epi×43 ppi and weighing 5.57 osy. The woven cloth was tested for abrasion using the standard Martindale test.

Table 5 shows the results of Martindale testing of Example 21 and Comparative Example 22. The cloth containing the inventive staple fiber improved the resistance to abrasion by greater than 65% over the abrasion of the cloth composed of the comparative staple fiber.

Example 23

An expanded PTFE filament was provided having the following properties:

Width: 50 mm; Thickness: 0.055 mm, Titer: 22,222 dtex; Density: 1.6 g/cm3. The filament was passed perpendicularly over a fibrillation (or towing roller) roller containing pin bars parallel to the axis of rotation. The pin bars, available for the Burkhardt Company located in Switzerland, having 30 pins per cm, each pin 2 mm in length and having a 30 degree projection from a position normal to the roller's surface. The pins were oriented such that the pins pointed in the direction away from the approaching filament such that the pins sweep into the filament as opposed to picking at the filament. The filament passing over the fibrillation roller was positioned such that at least 7 pin bars were in contact with the filament and the relative velocity between one pin bar to the velocity of the filament was 2.6 times faster. The resulting product was a tow ePTFE filament having a bulk titer of about 2,222 tex consisting of an array of discontinuous fibers having titer per denier per fiber (dpf) of about 15.

The tow ePTFE filament was crimped, and the tow filament was passed over a heated plate set to 170 degrees C. for a residence time of about 2 seconds and crimped by passing the filament through to two gear assembly consisting of two 100 mm diameter steel gears 50 mm wide having serrations parallel to the gear's axis on the outer surface such to produce a crimp consisting of serrations or indentations in the filament about ⅛″ (3.2 mm) apart.

The crimped tow ePTFE filament was cut into staple using a staple cutter similar to a staple cutter model number series 20 staple cutter available from the DM &E Company located in Shelby, N.C. Tow filament strands were combined such that the bulk titer of the combined yarn bundle was between 75,000 and 120,000 denier entering the crimper and staple cutter. The cut staple length was 25.4 mm long and the crimp level was at 8 crimps per inch (3.2 crimps per cm). The average caliper diameter of the ePTFE fibers was 36 microns.

A card sizing agent part number Selbana UN available from Pulcra Chemicals located in Munich, Germany was applied to the ePTFE staple fiber. The sizing agent was prepared using one part Selbana UN to six parts distilled water. The prepared sizing agent was applied using an amount of about 2% of the weight of the ePTFE staple fiber.

The sizing treated ePTFE staple fiber was hand blended with a polyester staple fiber, having a length of 38 mm and a fineness of 1.2 denier (1.33 dtex), brand named SFX available from the Sanfangxiang Group Co., Ltd. located in Jiangsu, China. The blended ratio was 10 percent ePTFE staple and 90 percent polyester staple. The hand blended staple was further blended using a mechanical blender available from the Hollingsworth Company.

A short staple card obtained from the Truetzschler Company model number DK903 received the blended staple from the Hollingsworth's mechanical blender. Autoleveling was used during carding where the grain weight of the sliver produced was targeted to be 75 grains per yard. Sliver exited the card and coiled into sliver cans using the can filling station model KH 750/800 from Truetzschler. The sliver was drawn on a drawing frame obtained from the Rieter Company model number RSB 851. The doubling was 6 slivers joined into one sliver and drafted at a ratio of 6.9 to 1 producing a sliver weight of 65 grains per yard. The sliver was doubled a second time combining 6 slivers into one and drafted at a ratio of 7.1 to 1 producing a weight of 55 grains per yard.

The sliver at 55 grains per yard was twisted and drafted at ratio of 10.9 to 1 to produce a roving at a weight of 1.65 Ne, hank roving. The roving was sent to the spinning room for spinning. The SIRO spin process was performed where two rovings are combined just prior to the drafting and twisting zones to yield a yarn weighing 30/1. The hank roving (HR) was 0.825 Ne (Number English or Cotton count) and the total draft during spinning was 36.4 to 1. The twist multiplier (T.M.) was 3.5. The yarn was waxed. The resulting yarn was observer to be suppler than a control yarn that was processed similarly but without the ePTFE staple content. The existence of several ends of the PTFE staple appeared on the surface of the yarn. A cross section of the yarn shows that the average caliper diameter of the ePTFE staple fiber was 67 micrometers and the average caliper diameter of the polyester staple fiber was 13 micrometers.

Example 24

The tow ePTFE filament described in Example 23 was crimped and cut into staple ePTFE fiber. The tow filament was passed over a heated plate set to 170 degrees C. for a residence time of about 2 seconds and crimped by passing the filament through to two gear assembly consisting of two 100 mm diameter steel gears 50 mm wide having serrations parallel to the gear's axis on the outer surface such to produce a crimp consisting of serrations or indentations in the filament about ⅛″ (3.2 mm) apart.

The crimped tow ePTFE filament was cut into staple using a staple cutter similar to a staple cutter model number series 20 staple cutter available from the DM &E Company located in Shelby, N.C. Tow filament strands were combined such that the bulk titer of the combined yarn bundle was between 75,000 and 120,000 denier entering the crimper and staple cutter. The cut staple length was 32 mm long and the crimp level was at 8 crimps per inch (3.2 crimps per cm), and the average caliper diameter of the fiber was 36 microns.

A card sizing agent part number Selbana UN available from Pulcra Chemicals located in Munich, Germany was applied to the ePTFE staple fiber. The sizing agent was prepared using one part Selbana UN to six parts distilled water. The prepared sizing agent was applied using an amount of about 2% of the weight of the ePTFE staple fiber.

The sizing treated ePTFE staple fiber was hand blended with a polyester staple fiber, having a length of 38 mm and a fineness of 1.2 denier (1.33 dtex) and an average caliper diameter of 12, brand named SFX available from the Sanfangxiang Group Co., Ltd. located in Jiangsu, China. The blended ratio was 10 percent ePTFE staple and 90% polyester staple. The hand blended staple was further blended using a mechanical blender available from the Hollingsworth Company.

A short staple card obtained from the Truetzschler Company model number DK903 received the blended staple from the Hollingsworth's mechanical blender. Autoleveling was used during carding where the grain weight of the sliver produced was targeted to be 75 grains per yard. Sliver exited the card and coiled into sliver cans using the can filling station model KH 750/800 from Truetzschler. The sliver was drawn on a drawing frame obtained from the Rieter Company model number RSB 851. The doubling was 6 slivers joined into one sliver and drafted at a ratio of 6.9 to 1 producing a sliver weight of 65 grains per yard. The sliver was doubled a second time combining 6 slivers into one and drafted at a ratio of 7.1 to 1 producing a weight of 55 grains per yard.

The sliver at 55 grains per yard was twisted and drafted at ratio of 10.9 to 1 to produce a roving at a weigh of 1.65 Ne, hank roving. The roving was sent to the spinning room for spinning. The SIRO spin process was performed where two rovings are combined just prior to the drafting and twisting zones to yield a yarn weighing 30/1. The hank roving (HR) was 0.825 Ne and the total draft during spinning was 36.4 to 1. The twist multiplier (T.M.) was 3.5. The yarn was waxed.

The resulting yarn was observer to be suppler than a control 100% polyester yarn that was processed similarly but without the ePTFE staple content. The yarn appears less hairy than the control yarns composed of 100% polyester.

Although the foregoing has been described in some detail by way of illustration and example for purposes of clarity and understanding, one of skill in the art will appreciate that certain changes and modifications can be practiced within the scope of the appended claims. In addition, each reference provided herein is incorporated by reference in its entirety to the same extent as if each reference was individually incorporated by reference. 

1. A yarn comprising: i) a plurality of fluoropolymer staple fibers with an average caliper diameter of at least 15 microns, and ii) a plurality of non-fluoropolymer staple fibers, wherein the ratio of the average caliper diameter of the fluoropolymer staple fibers to the average caliper diameter of the non-fluoropolymer staple fibers in the yarn is 1.2 to
 20. 2. The yarn of claim 1, wherein the non-fluoropolymer staple fibers comprise one or more staple diameters.
 3. The yarn of claim 1, wherein the non-fluoropolymer staple fibers comprise one or more synthetic staple fibers, one or more natural fibers or a combination thereof.
 4. (canceled)
 5. The yarn of claim 1, wherein the fluoropolymer comprises expanded polyetetrafluoroethylene.
 6. The yarn of claim 1, wherein the fluoropolymer staple fibers comprise expanded polyetetrafluoroethylene having a density of 1.9 grams per cubic centimeter (g/cm³) or less.
 7. The yarn of claim 1, further wherein the yarn contains at least one of an antistatic component, a cohesion component, a wax, antimicrobial material, fragrance, antimildew agent, insect repellants, cooling agents, heating agents, analgesics, oleophobics, oleophilics, FR materials, an organic pigment, an inorganic pigment, a signature identification marker or a combination thereof.
 8. The yarn of claim 1, to wherein the fluoropolymer staple further comprises at least one of an organic filler, an inorganic filler, a thermal conductor, an electric conductor, a thermal insulator, an electrical insulator, silver, carbon black, a color pigment, a color lake, a color dye, a size/dimensionally enhancing material, a signature identification marker, a UV absorber, a light reflecting material or a combination thereof.
 9. The yarn of claim 1, wherein the yarn further comprises one or more continuous filaments.
 10. (canceled)
 11. The yarn of claim 1, wherein the weight percent of the fluoropolymer staple fibers is 35% by weight or less, based on the total weight of the yarn.
 12. (canceled)
 13. (canceled)
 14. A yarn comprising: (i) a plurality of fluoropolymer staple fibers having a rectangular cross-section and (ii) a plurality of non-fluoropolymer staple fibers, wherein the average caliper diameter of the fluoropolymer staple fibers is between 15 and 500 microns and the average caliper diameter of the non-fluoropolymer staple fibers is between 0.1 and 40 microns.
 15. The yarn of claim 14, wherein the non-fluoropolymer staple fibers comprise one or more staple diameters.
 16. The yarn of claim 14, wherein the non-fluoropolymer staple fibers comprise one or more synthetic staple fibers, one or more natural fibers or a combination thereof.
 17. (canceled)
 18. The yarn of claim 14, wherein the fluoropolymer staple fibers comprise expanded Polyetetrafluoroethylene.
 19. The yarn of claim 14, wherein the fluoropolymer staple fibers comprise expanded polyetetrafluoroethylene having density of 1.9 g/cm³ or less.
 20. The yarn of claim 14, wherein the yarn contains at least one of an antistatic component, a cohesion component, a wax, an antimicrobial material, a fragrance, an antimildew agent, an insect repellant, a cooling agent, a heating agent, an analgesic, an oleophobic, an oleophilic, an FR material, an organic pigment, an inorganic pigment, a signature identification marker or a combination thereof.
 21. The yarn of claim 14, wherein the yarn further comprises at least one of an organic filler, an inorganic filler, a thermal conductor, an electric conductor, a thermal insulator, an electric insulator, silver, carbon black, a color pigment, a color, a color dye, a size/dimensionally enhancing material, a signature identification marker, a UV absorber, a light reflecting material or a combination thereof.
 22. The yarn of claim 14, wherein the yarn further comprises one or more continuous filaments.
 23. (canceled)
 24. The yarn of claim 14, wherein the weight percent of fluoropolymer staple fibers is 35% by weight or less, based on the total weight of the yarn.
 25. (canceled)
 26. (canceled)
 27. An article comprising a yarn, the yarn comprising: i) a plurality of expanded polytetrafluoroethylene (ePTFE) staple fibers having a length between 1 inch and 1.25 inch with an average caliper diameter of at least 30 microns, and ii) a plurality of polyester staple fibers, wherein the staple fibers i) and ii) are formed into the yarn, wherein the weight percent of the ePTFE staple fibers to the weight percent of the overall yarn is 10% by weight and the ratio of the average caliper diameter of the ePTFE staple fibers to the average caliper diameter of the polyester staple fibers in the yarn is 1.2 or greater.
 28. An article comprising a yarn, the yarn comprising: (i) a plurality of expanded PTFE (ePTFE) staple fibers having a rectangular cross-section and (ii) a plurality of polyester staple fibers formed into a yarn, wherein the ePTFE staple fibers are present in an amount of 10% by weight of the overall yarn, and wherein the average caliper diameter of the expanded PTFE staple fibers is between 30 and 500 microns and the average caliper diameter of the polyester staple fibers is between 10 and 40 microns. 